Digital transient discriminator with noise spike clipping

Abstract

A digital discriminator having circuit means for discriminating a unidirectional transient in the input signal over a two or more compute cycle period. Noise spike clipping by providing a programmable constant in a feedback circuit is disclosed and serves to clip the signal in one given direction giving positive sensitivity of that signal in the other direction.

We claim: 
     
       1. For a sensor that produces an input signal to logic means for determining the unidirectional transient in said input, said logic including means responsive to an output signal for generating a first delayed cycle signal and a second delayed cycle signal, first summer means for combining the first delayed cycle signal with a constant, second summer means for combining the second delayed cycle signal with said input signal and a maximum selector means responsive to said input signal and the output of said first summer means for selecting the higher value of either said input signal or the output of said first summer means to generate an input signal to said generating means. 
     
     
       2. For a sensor as in claim 1 wherein said constant is a negative value and said input signal has a positive and negative polarity and said logic means is a feed forward processor processing said input signal so that its positive polarity is at its rate of change value. 
     
     
       3. Apparatus for generating a unidirectional rate of change signal from an input signal having means for clipping noise spikes in a given polarity of said input including a maximum selector responsive to said input signal and the output of a first summer for generating an input signal to a first cycle delay signal and a second cycle delay signal means, said first summer combining a first cycle delay signal with a constant having a negative value, and a second summer responsive to said input signal and the output of said first cycle delay signal and second cycle delay signal means for producing an output signal indicative of the rate of change value of the positive polarity of said input signal. 
     
     
       4. In an automatic rate of change controller in response to an input signal comprising the steps of: generating a first delay cycle signal and a second delay cycle signal in response to an output signal,   selecting the output signal utilized in the above step of generating from the higher value of the input signal or the first delay cycle signal combined with a preselected constant for clipping noise spikes in a given polarity,   summing the input signal with the second delay cycle signal whose value is indicative of a unidirectional transient of the input signal.